A physician typically accesses and visualizes tissue within a patient's gastrointestinal (GI) tract with a long, flexible endoscope. For the upper GI, a physician may insert a gastroscope into the sedated patient's mouth to examine and treat tissue in the esophagus, stomach, and proximal duodenum. For the lower GI, a physician may insert a colonoscope through the sedated patient's anus to examine the rectum and colon. Some endoscopes have a working channel, typically about 2.5-3.5 mm in diameter, extending from a port in the handpiece to the distal tip of the flexible shaft. A physician may insert medical instruments into the working channel to help diagnose or treat tissues within the patient. Physicians commonly take tissue biopsies from the mucosal lining of the GI tract using a flexible, biopsy forceps through the working channel of the endoscope.
Insertion of a flexible endoscope, especially into the colon, is usually a very time-consuming and uncomfortable procedure for the patient, even when sedated with drugs. A physician often needs several minutes to push a flexible endoscope through the convoluted sigmoid, descending, transverse, and ascending portions of the colon. The physician may diagnose and/or treat tissues within the colon either during insertion or removal of the endoscope. Often the flexible endoscope “loops” within the colon, such as at the sigmoid colon or at the splenic flexure of the colon, so that the endoscope can stretch the portion of colon containing it. This stretching can cause pain to the patient even though sedation is used. Depending on the anatomy of the patient and the skill of the physician in manipulating the flexible endoscope, some portions of the colon may be unexamined, thus increasing the risk of undiagnosed disease.
Given® Engineering LTD, Yoqneam, Israel, sells a device in the U.S. called the M2A™ Swallowable Imaging Capsule. The device contains a tiny video camera, battery, and transmitter. It is propelled through the gastrointestinal tract by natural peristalsis. The device is currently used for diagnostic purposes and passes through the intestinal tract with a velocity determined by the natural, peristaltic action of the patient's body. World Publication WO 0108548A1 filed by C. Mosse, et al. describes a self-propelling device adapted to travel through a passage having walls containing contractile tissue. The applicants disclose that the device is particularly useful as an enteroscope and may also carry objects such as feeding tubes, guide wires, physiological sensors or conventional endoscopes within the gut. A summary of other alternatives to push endoscopy can be found in “Technical Advances and Experimental Devices for Enteroscopy” by C. Mosse, et al, published in Gastrointestinal Endoscopy Clinics of North America, Volume 9, Number 1, January 1999: pp. 145-161.
During each procedure, a physician typically needs to pass medical instruments in and out of the colon numerous times. Current endoscopes have working channels (also called biopsy channels) for passing instruments into the lumen for performing procedures on the lumen wall with endoscopic visualization. It is important that variations of a self-propelled intraluminal device also have such an integral working channel for the passage of instruments into the lumen, rather than requiring that a separate endoscope with a working channel be pulled behind the self-propelled device. Reducing what must be carried into the lumen may minimize the contractile force of the luminal walls required for self-propulsion of the device. In addition, the need for a conventional endoscope may be completely eliminated, along with associated costs, if a self-propelled device also had an integral working channel for performing diagnosis and/or therapy inside the lumen.
Currently physicians also use stains such as methylene blue dye, or contrast agents such as indigo carmine, to identify diseased tissues within the lumen of the colon or esophagus. Such stains and agents, which we shall generally refer to hereinafter as diagnostic agents, may be passed into the lumen via the working channel of the endoscope. The diagnostic agent highlights the diseased tissue, such as a polyp or a cancerous lesion, for identification by the physician. Applying diagnostic agents may be messy and require special additional steps during and after the examination procedure, including the thorough removal of the diagnostic agent from the endoscope prior to reuse on another patient. The ability to apply a minimal amount of such diagnostic agents evenly on the luminal wall, rather than washing the luminal wall with large amounts of diagnostic agent that then collects in the lumen or drains onto the examination table, for example, is an attractive option for physicians. Also, using a low cost, potentially disposable device such as a self-propelled intraluminal device provides physicians with a desirable alternative to cleaning the diagnostic agent from a conventional, reusable, flexible endoscope.
What is needed, therefore, is a self-propelled, intraluminal device that includes an integral, working channel for the passage of medical instruments in order to treat tissues in the lumen. What is also needed is a self-propelled, intraluminal device that dispenses a diagnostic agent to identify diseased tissue in the lumen.